Stoppers
Stoppers, also known as bungs, are used to give an airtight seal to laboratory flasks and test tubes by fitting tightly inside the neck of the container and preventing material from spilling. Stoppers can be made of glass, cork, rubber, or silicone. They are typically designed with a conical shape, but straight, flanged, and tapered options are also available.
Stoppers are the preferred choice for many applications requiring a tighter seal or a greater degree of chemical resistance. They also provide a good seal when a solution needs to be shaken or mixed without spilling. Stoppers are generally cylindrical in shape and have a tapered bottom end. They may be marked with a stopper number or size on the top and bottom diameters of the stopper. Sizing can vary among manufacturers.
Stoppers are available in a solid design or with holes known as positions placed in the top. Positions allow easy access to the material contained in the sealed vessel by pipettes, tubing, or other equipment without full removal of the stopper.
What Types of Stoppers Are Available?
• Turnover stoppers have external serrations to create an excellent internal seal combined with a flexible turnover sleeve that folds down over the container’s neck to create a double seal
• Serum bottle or vial stoppers have two or three legs with external serrations or straight sides and a flanged top to create an airtight seal
• Straight bromobutyl plug-type stoppers provide a maximum seal for vials and serum bottles with a straight-wall glass finish
• Ultra-pure, straight bromobutyl plug-type stoppers provide high chemical purity and low gas permeability. They offer excellent performance during freeze drying processes such as lyophilization, where stoppers must remain stable during transfer and sublimination phases
• Silicone recessed septa stoppers are non-toxic and have external serrations to create an effective internal seal
Ace Glass, Inc. 45/50 PTFE Stopper with Polypropylene Extraction Nut, Solid
45/50 standard taper PTFE stopper with polypropylene extraction nut for easy removal from outer joints.
Ace Glass, Inc. 10/18 PTFE Stopper with Polypropylene Extraction Nut, Solid
10/18 standard taper PTFE stopper with polypropylene extraction nut for easy removal from outer joints.
Ace Glass, Inc. 24/40 PTFE Stopper with Polypropylene Extraction Nut, Solid
24/40 standard taper PTFE stopper with polypropylene extraction nut for easy removal from outer joints.
Ace Glass, Inc. #22 PTFE Stopper with Polypropylene Extraction
#22 standard taper PTFE stopper with polypropylene extraction nut for easy removal from outer joints.
Sigma Aldrich Fine Chemicals Biosciences Precision SealR rubber sep
The recommended choice for use with organic chemicals and solvents pressure applications and cannulation techniquesPrecision Seal septa are designed specifically for the rigorous requirements of chemical applications.Precision fit Precision Seal septa have a longer tapered plug that seats firmly inside the glass joint or tube providing a sealing surface that is 50 to 80% greater than standard sleeve stoppers. The inner seal design of Precision Seal septa minimizes chemical and solvent vapor migration up the joint to the sleeve which can swell leak or fail from exposure. The surface texture of the rubber is similar to that of a ground glass joint and resists movement once seated.Non-contaminating Precision Seal natural rubber is lower in solvent extractables 1.9% vs. standard sleeve stoppers 5-6%. Precision Seal rubber is higher in density to minimize the effects of solvent degradation. They are manufactured from a single certified lot for absolute consistency.Safet
Chemglass Life Sciences #19 PTFE Stopper, Green Handle
#19 PTFE Stopper, Green Handle. Flask length PTFE stopper with color coded handle.
Chemglass Life Sciences #13 PTFE Stopper, Orange Handle
#13 PTFE Stopper, Orange Handle. Flask length PTFE stopper with color coded handle.
Chemglass Life Sciences #38 PTFE Stopper, Black Handle, Hollow
#38 PTFE Stopper, Black Handle, Hollow. Flask length PTFE stopper with color coded handle.
Cole-Parmer Twistit white rubber stopper, size 6
Use these versatile Twistit stoppers as either a solid, one-hole, two-hole, or three-hole stopper. Simply twist off a bottom seal to open a hole. The soft resilient natural rubber stays pliable over a long period and withstands laboratory conditions without hardening. Stoppers retain resiliency even after repeated autoclaving. Each stopper has its size in raised figures on top. Available in black or white rubber. Autoclavable.